Combine flour & sugar and slowly add 1 cup cold milk, blending until smooth. Add to hot milk and cook in double boiler over medium heat for 8 minutes. Add small amount of hot mixture to eggs and return all to hot mixture. Cook another 2 minutes, stirring constantly.
Combine cream, salt & vanilla and remaining cup of milk; slowly add hot mixture.
Refrigerate for a few hours before freezing in regular crank freezer.
Additions of grated chocolate, nuts, marshmallows, diced fruit, etc., may be added when mixture is about half frozen.